<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        .body-content {
            float: left;
            width: 100%;
        }
        .left {
            float: left;
            width: 190px;
            margin-left: -100%;
            background-color:gray;
        }
        .right {
            float: left;
            width: 230px;
            margin-left: -230px;
            background-color:gray;
        }
        .content {
            margin: 0 230px 0 190px;
            background-color:red;
        }
    </style>
</head>
<body>
<div class="body-content">
    <div class="content">content</div>
</div>
<div class="left">left</div>
<div class="right">right</div>
</body>
</html>